1. Technical Field
The present invention relates to a light divider and a magnetism measurement apparatus.
2. Related Art
There is a known optical sensor array in which a plurality of optical sensors are arranged and each of them optically measures a physical quantity (physical state). An optical sensor array using optically-pumped magnetism sensors as the optical sensors is used, for example, in a magnetocardiograph, which measures a magnetic field produced by the heart of a living organism, and a magnetoencephalograph. To operate the optical sensor array, light from a light source needs to be divided into light fluxes, which need to be incident on the optical sensors. For example, JP-A-2008-277279 discloses a technology in which a plurality of polarizing beam splitters (PBSs) are disposed and divide laser light into a large number of light fluxes.
The transmittance (or reflectance) of a polarizing beam splitter typically varies by about several percent. Therefore, when light repeatedly passes through a plurality of polarizing beam splitters, it is difficult to make the amounts of divided light fluxes the same due to an accumulated transmittance error.